Attachment of nonmetallic articles to metallic substrates

ABSTRACT

Ceramic articles such as segments in the form of blocks or plates are secured to an underlying metallic surface by means of metal retainers which are inserted in holes or openings extending through the ceramic material. The retainers have frustoconical outer surfaces which engage corresponding surfaces on the ceramic segments. The retainers are securely held to the metal surface by welding. The welding is accomplished by inserting a welding rod through a passage provided through the center of the metal retainer and forming a weld bead that extends from the metallic surface into the passage and beyond an internal flange located adjacent the inner end of said passage.

United States Patent inventor Louis G. Kutz/er Latrobe, Pa. Appl. No.33,935 Filed May 1,1970 Patented Nov. 30, 1971 Assignee The CarborundumCompan Niagara Falls, NY.

Continuation-impart of application Ser. No. 749,833, Aug. 2, 1968, nowabandoned. This application May l, 1970, Ser. No. 33,935 1 ATTACHMENT OFNONMETALLIC ARTICLES TO Primary Examiner-J. V. Truhe Assistant ExaminerL. A. Schutzman Atiorney K. W. Brownell ABSTRACT: Ceramic articles suchas segments in the form of blocks or plates are secured to an underlyingmetallic surface by means of metal retainers which are inserted in holesor openings extending through the ceramic material. The retainers havefrustoconical outer surfaces which engage corresponding surfaces on theceramic segments. The retainers are securely held to the metal surfaceby welding. The welding is accomplished by inserting a welding rodthrough a passage provided through the center of the metal retainer andforming a weld bead that extends from the metallic surface into thepassage and beyond an internal flange located adjacent the inner end ofsaid passage.

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' LOUIS G. KUTZER ATTACHMENT'OF NONMETALLIC ARTICLES TO METALLICSUBSTRATES BACKGROUND OF THE DISCLOSURE This application is-in part acontinuation of copending application Ser. No.749,833, filed Aug. 2,1968, now abandoned.

This invention relates to the attachment of replaceable liners or coversfor metallic surfaces, and more particularly, to the attachment andreplacement of ceramic segments on metal surfaces.

A ceramic lining. is utilized in conveyor chutes, conveyor buckets andsimilar installations where abrasive or corrosive material wouldcause'such rapid wear that a bare metallic surface would be impractical.Also, in certain applications it is desirable to have a nonmetallicsurface that is completely devoid of metal, depressions and foreignmaterials. Although it is desirable to use ceramic materials in suchinstallations, conventional methods of securing the ceramic segments onthe metal surface do not permit a segment to be conveniently replaced ifit should break or become worn after the entire lining has beeninstalled.

Attempts have been made to mold metal fasteners into the ceramicarticles. For example, the metal surface may have holes for receivingbolts and corresponding nuts may be molded into the ceramic segment.Such an arrangement is impractical where the outer surface of the metalbacking plate is not exposed or accessible. Furthermore, sockets must beformed in the ceramic segment and the nuts must be accurate lypositioned in the sockets and cemented in place, so that the edges ofthe ceramic segments will fit properly with adjacent segments. Incertain other prior installations, the ceramic segments are lockedtogether and secured to the backing plate by a frame or other meansextending around their perimeter. This arrangement makes it difficult toreplace individual segments of ceramic because of the interlocking, bymeans such as shoulders, between adjacent segments.

Accordingly, it is an object of this invention to provide a method andattachment means for rapidly installing and replacing individual ceramicsegments on metal surfaces.

A further object of this invention is to provide means for installingceramic linings of various thicknesses and various materials and over awide range of sizes.

Another object of this invention is to provide for readily attachingceramic segments to the metallic surface of a backing plate at variouslocations without requiring alteration of the backing plate.

SUMMARY'OF THE INVENTION These objects are accomplished in accordancewith a preferred embodiment of the invention by employing ceramic blocksor segments which have frustoconical socket portions extendingtherethrough. A metallic retainer having a frustoconical outer surfaceis positioned in the socket portion of the ceramic article so that thelower end of the retainer is spaced slightly above the underlyingmetallic support surface. The retainer has a passage extendingthroughout its length and the passage has a sufficiently large diameterto allow a welding rod to be inserted inthe passage. With the ceramicarticle in position on the metal-surface, and with the retainer insertedin the socket portion, the slopes of the frustoconical surfaces of theretainer and the socket portion being substantially the same, a weldingrod is inserted in the passage in the retainer and a weld bead is formedin the interior of the retainer joining together the retainer and themetallic surface. The retainer may be readily detached from the metalsurface by drilling out the weld bead.

DESCRIPTION OF THE DRAWINGS This preferred embodiment is illustrated inthe accompanying drawings in which:

FIG. 1 is a top planview of a metal bucket having ceramic liner segmentssecured therein in accordance with this inventron;

FIG. 2 is a cross-sectional view of the bucket along the line 2-2 inFIG. 1;

FIG. 3 is an enlarged cross-sectional view of the bucket along the line3-3 in FIG. 1;

FIG. 4 is a detail view of a retainer in longitudinal cross section;

FIG. 5 is a top plan view of the retainer illustrated in FIG. 4;

FIG. 6 is a top plan view of a modified liner installation;

FIG. 7 is a cross-sectional view of the modified installation along theline 7-7 in FIG. 6; and

FIG. 8 is a longitudinal cross-sectional view of a further modifiedretainer.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 and 2 are a somewhatschematic illustration of a skip bucket which might be used forconveying corrosive material such as coke from one location to another.The bucket 2 includes a metallic shell 4 forming the bottom, end walls,and side walls of the bucket. Superimposed on the shell surfaces in theinterior of the bucket are a plurality of ceramic liner segments 6.These liner segments 6 are individually secured to the shell 4 bymetallic retainers 8, as shown in FIG. 3.

A retainer 8 is shown in longitudinal cross section in FIG. 4 and in topplan view in FIG. 5. The retainer 8 has a central passage 10 extendingfrom one end 12 to the opposite end 14. A frustoconical outer surface 16coaxial with the passage I0 extends between the ends 12 and 14 of theretainer. An annular shoulder or flange 18 is formed in the interior ofthe passage 10 adjacent the small end 14 of the retainer.

The ceramic segment 6 has a socket 20 that extends from the upper,exposed surface of the segment to the lower surface which is adjacentthe shell 4. The segments 6 are typically formed of molded and firedceramics, such as alumina, or other nonmetallic heat and corrosiveresistant material. The socket 20 has an inner frustoconical portion 22and an outer cylindrical portion 24. The taper of the frustoconicalportion 22 is approximately the same as that of the external surface 16of the retainer 8. The length of the tapered portion 22, however, isslightly longer than the length of the retainer 8, so that the small end14 of the retainer is spaced above the lower surface of the segment 6.

A layer 26 of bonding material, such as cement, adhesive, or mastic isapplied to the inner surface of the metallicshell 4 to compensate forirregularities in the surface. A weld bead 28 is deposited at the bottomof the passage 10 by suitable welding techniques. The weld bead 28 isfused to the inner surface of the shell 4 and extends into the passage10 beyond the shoulder 18 therein so that the retainer is rigidlysecured to the shell 4. A cylindrical cover disc 30 is inserted in theupper, cylindrical portion 24 of the socket 20 to protect the retainer 8from corrosive conditions existing at the upper surface of the segment6. The cover 30 is preferably formed of the same material as the segment6 and sealed in place by a suitable adhesive layer 32 applied to theperipheral and lower surfaces thereof.

In order to install the segments 6 in the bucket 2, a segment ispositioned as desired on the shell 4 after the bonding layer 26 has beenapplied either to the lower surface of the segment 6 or to the uppersurface of the shell 4. When the segment 6 is properly positioned on theshell 4, the retainer 8 is inserted in the socket 20. A shielded weldingelectrode is inserted through the passage 10 and the weld bead 28 isformed. Subsequently, the cover 30 is inserted over the retainer 8.Preferably the upper surface of the cover is flush with the upper faceof the ceramic segment 6. The process is repeated for each segment untilall the segments have been installed on the interior wall of the shell4.

An important advantage of this invention is that the appropriateretainers may be readily removed in the event that one or more of thesegments require replacement. To remove a retainer a drill is insertedin the central passage thereof to drill out the weld bead 28 and theshoulder 18 of the retainer.

The retainer is thereby released so that the segment which was securedin place by the retainer can now be removed. This permits the individualreplacement of segments without disturbing adjacent segments.

In FIGS. 6 and 7 there is illustrated a modification of the presentinvention which permits the use of fewer metal retainers since a singleretainer may be employed to hold the corners of a plurality ofcontiguous nonmetallic blocks or segments, each of which has a socketportion with arced periphery which together form a conical socket forthe retainers. As shown therein, a plurality of rectangular,nonmetallic, such as ceramic, segments 34 are secured to a metal shell36 by a frustoconical retainer 38 at adjacent corners of the segments.At each comer of the segments a socket portion, having the form of atapered quadrant 40, is provided, the four adjacent socket portionscooperating to form a common socket 42 for the retainer 38. The segments34 have substantially straight sides which are perpendicular to theupper and lower surfaces and cement or adhesive 44 is applied betweenthe adjacent segments and around the exterior face of the retainer 38. Asimilar bonding layer 46 may be applied between the surface of the shell36 and the segments 34, if necessary or desired. The layers 44 and 46 aswell as the adhesive layers 26 and 32 are exaggerated in thickness incertain of the drawings.

The retainer 38 has a central passage 48 extending throughout the lengthof the retainer and concentric with the frustoconical outer surface. Atthe lower end of the passage 48, an inwardly directed annular shoulder50 is provided. A weld bead 52 is formed at the lower end of theretainer 38 by suitable welding techniques, and the weld bead rigidlyjoins the retainer to the metallic shell 36. As shown in FIG. 7, thelarger upper end of the retainer 38 is approximately coplanar with theexposed surfaces of the segments 34. if the segments 34 are mounted on achute or a slide, or in some environment where the metal retainer 38 isnot exposed to excessive abrasion or corrosion, the retainer may remainuncovered. If desired, however, the retainer 38 may be shorter in lengththan the thickness of the segments with which it is used and a ceramicplug or disc may be inserted in the socket above it, in a manner similarto that used in the embodiment of FIGS. 1-5.

In order to install a liner in a metal shell according to the theembodiment of FIGS. 6 and 7, the segments 34 are arranged as shown inFIG. 6 on the metallic surface of the shell 36, and the retainer 38 isinserted in the socket 42 formed by the socket portions of the adjacentsegments. A welding rod is inserted through the passage 48 to form aweld bead 52 engaging the shell 36 and extending above the shoulder 50formed in the passage 48. Similar retainer installations are provided ateach corner of the various segments 34, so that the segments are rigidlysecured to the shell 36.

FIG. 8 illustrates a further modified fomi of retainer. This retainer 54has a frustoconical outer surface and a frustoconical passage 56therethrough so that the thickness of the wall of the retainer remainssubstantially constant. At the lower end of the retainer, however, anannular shoulder 58 projects inwardly in the passage 56 to cooperatewith a weld bead for securing the retainer 54 to a metallic surface. Thelarge opening at the upper end of the retainer 54 and the short axiallength of the retainer are particularly suitable for welding retainersof small size, because of the relatively larger clearance that isprovided.

The attachment of nonmetallic, such as ceramic, wear plates or segmentsto a metallic shell in accordance with this invention may be carried outquickly and easily. The use of metal retainers which are welded to theshell or other metal backing is readily adapted to a variety ofthicknesses of segments, and a wide variety of nonmetallic materials forthe segments.

While this invention has been illustrated and described in severalpreferred embodiments, it is recognized that variations and changes maybe made therein without departing from the invention as set forth in theclaims.

What is claimed is: 1. In combination, an underlying metal surface; anonmetallic article superimposed on said underlying surface. saidarticle having a face adjacent said underlying surface and a faceopposite thereto and having a socket portion extending from one of saidfaces to the other, the periphery of said socket portion being arced incross section and at least a portion thereof being of decreasing radiusas it approaches the first-mentioned face of said article; a metallicretainer having a frustoconical outer surface with a slope approximatelythe same as that of said socket portion, within and closely fitting theportion of said socket portion having the decreasing radius, saidretainer having a passage therethrough coaxial with said frustoconicalsurface and an annular, inwardly directed flange projecting into saidpassage adjacent the smaller end of said retainer; and a weld beadsecuring together said underlying surface and said retainer andextending into said passage beyond said flange, whereby said retainer isheld close to but spaced from said underlying surface and saidnonmetallic article is firmly retained on said underlying surface.

2. The combination set forth in claim 2 wherein the nonmetallic articleis ceramic.

3. The combination set forth in claim 2 wherein the retainer is shorterin length than the thickness of said ceramic article.

4. The combination set forthin claim 3 wherein a cover for said retaineris provided in the upper portion of said socket portion.

5. The combination set forth in claim 4 wherein said cover is the samematerial as said ceramic article.

6. The combination as set forth in claim 2 wherein said retainer isfitted into a plurality of adjacent socket portions each said portionbeing formed in a separate one of a plurality of contiguous ceramicarticles.

7. A method of installing a nonmetallic article on an underlyingmetallic surface, said article having a face adjacent said underlyingsurface and a face opposite thereto and having a socket portionextending from one of said sides to the other, the periphery of saidsocket portion being arced in cross section and at least a portionthereof being of decreasing radius as it approaches the first-mentionedface of said article, which comprises fitting a metallic retainer insaid socket portion of decreasing radius, said retainer having afrustoconical outer surface with a slope approximately the same as thatof said socket portion and having a passage therethrough coaxial withsaid frustoconical surface and an annular, inwardly directed flangeprojecting into said passage adjacent the smaller end of said retainer,inserting a welding'rod through said passage to said underlying surface,and depositing a weld bead on said underlying surface and into saidpassage above said flange.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 624,344 Dated November 30, 1971 Louis G. Kutzer Inventor(s) It is certifiedthat error appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

In column 4, lines 33-34, claim 2 should read:

- 2. The combination set forth in claim 1 wherein the nonmetallicarticle is ceramic.

Signed and sealed this 12th day of '.September- 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GO'ITSCHALK Attasting Officer Commissionerof Patents FORM PC40 uscoMM-oc 6G376-P69 Q U S GOVERNMENY PRINTINGOFFICE V969 0-365-33l

1. In combination, an underlying metal surface; a nonmetallic articlesuperimposed on said underlying surface, said article having a faceadjacent said underlying surface and a face opposite thereto and havinga socket portion extending from one of said faces to the other, theperiphery of said socket portion being arced in cross section and atleast a portion thereof being of decreasing radius as it approaches thefirst-mentioned face of said article; a metallic retainer having afrustoconical outer surface with a slope approximately the same as thatof said socket portion, within and closely fitting the portion of saidsocket portion having the decreasing radius, said retainer having apassage therethrough coaxial with said frustoconical surface and anannular, inwardly directed flange projecting into said passage adjacentthe smaller end of said retainer; and a weld bead securing together saidunderlying surface and said retainer and extending into said passagebeyond said flange, whereby said retainer is held close to but spacedfrom said underlying surface and said nonmetallic article is firmlyretained on said underlying surface.
 2. The combination set forth inclaim 2 wherein the nonmetallic article is ceramic.
 3. The combinationset forth in claim 2 wherein the retainer is shorter in length than thethickness of said ceramic article.
 4. The combination set forth in claim3 wherein a cover for said retainer is provided in the upper portion ofsaid socket portion.
 5. The combination set forth in claim 4 whereinsaid cover is the same material as said ceramic article.
 6. Thecombination as set forth in claim 2 wherein said retainer is fitted intoa plurality of adjacent socket portions each said portion being formedin a separate one of a plurality of contiguous ceramic articles.
 7. Amethod of installing a nonmetallic article on an underlying metallicsurface, said article having a face adjacent said underlying surface anda face opposite thereto and having a socket portion extending from oneof said sides to the other, the periphery of said socket portion beingarced in cross section and at least a portion thereof being ofdecreasing radius as it approaches the first-mentioned face of saidarticle, which comprises fitting a metallic retainer in said socketportion of decreasing radius, said retainer having a frustoconical outersurface with a slope approximately the same as that of said socketportion and having a passage therethrough coaxial with saidfrustoconical surface and an annular, inwardly directed flangeprojecting into said passage adjacent the smaller end of said retainer,inserting a welding rod through said passage to said underlying surface,and depositing a weld bead on said underlying surface and into saidpassage above said flange.